A toll-collecting system and a method of the aforementioned type are disclosed in DE 43 44 433 A1. In this prior method, the current local coordinates are registered by means of a GPS receiver and compared with coordinates of the access and exit points of a highway road section as internally stored in an electronic vignette and, when the coordinates agree, they are transmitted by way of the digital mobile network to an accounting center outside the vehicle, in which accounting center the transmitted data are used to compute the number of highway kilometers traveled and the highway fees thus due.
WO 95/20801 discloses a method of, and system for, determining toll fees for traffic routes and/or traffic areas in which the positional data of the vehicle are registered by means of a satellite-aided position calculating system and are compared with the position of virtual toll-collecting points. The positional data can be transmitted to a master station outside the vehicle for computation of the toll fees, or computation of the charges can alternatively take place in a toll-charging device inside the vehicle and the calculated charges then be transmitted to the master station, where they can be deducted from an account.
WO 99/33027 describes a method of collecting toll fees, in which the current position of the vehicle is determined by means of a satellite-aided position calculating system and is compared with the position of a virtual toll-collecting point for the purpose of computing toll fees, and when a vehicle passes through a physical toll station, a communication connection is set up between the vehicle and a central master toll station for the purpose of paying the accrued toll fees. After the payment transaction has been carried out, a communication connection is set up between the toll station and the vehicle, via which a message confirming the correct payment of the toll fee is transmitted.
The known methods suffer from the drawback that when the position calculating system used, for example, the GPS system, fails, position computation can no longer take place. In such a case, the effectiveness of toll charging using the prior tolling systems can no longer be guaranteed.
It is therefore an object of the invention to overcome the aforementioned drawbacks.
This object is achieved, according to the invention, with a process of the type mentioned above in that the vehicle is equipped with a transmitter/receiver unit that is adapted to exchange data with a cellular radio network, in which at least one cell identifier is assigned to each cell of the radio network, and when there is at least partial failure of the position calculating system, the measured cell IDs are checked to ascertain whether the road section being used by the vehicle is a toll road section.
Due to the possibility of determining whether a used road section requires toll payment by means of data exchange with a radio network, correct toll charging can still be guaranteed when the primary (eg, satellite-aided) position calculating system fails. By a primary position-calculating system we mean, in this document, any conventional position-calculating system by means of which the position of a vehicle can be determined under normal operating conditions.
In a preferred variant of the invention, at least two cells of the radio network are assigned to a toll road section.
Conveniently, cell identification is continuously measured in the transmitter/receiver unit of the vehicle. Advantageously, the radio network is a GSM network, whilst the primary position-calculating system can be satellite-aided as is the case, for example, in a GPS system.
Other advantages can be achieved by weighting each cell assigned to a toll road section by a weight characteristic of the relevance of this cell for the recognition of the toll road section.
For identification of a toll road section, the sum of the weights of at least two cells assigned to this road section and received in the transmitter/receiver unit can be formed, and when a predefined threshold value of the sum of said weights is exceeded, the currently used road section is classified as being a toll road section.
Conveniently, the weight of a cell corresponds to not more than the maximum number of cells assigned to the toll road section.
Furthermore, the number of currently traversed cells assigned to a toll road section can be counted with reference to the cell IDs received by the transmitter/receiver unit and the count will be checked to ascertain whether a predefined number of traversed cells has been exceeded.
Furthermore, a check can be made to ascertain whether at least two successive cell IDs received by the transmitter/receiver unit are assigned to the same toll road section.
A system based on vehicle localization is particularly suitable for carrying out the method of the invention, for example a toll-collecting system of the type mentioned above in which the road section identifying unit has, in addition to the position-calculating unit, a transmitter/receiver unit that is adapted to exchange data with a cellular radio network, in which at least one cell identifier is assigned to each cell of the radio network and the road section identifying unit is adapted in such a manner that when there is at least partial failure of the position calculating system the at least one cell ID is checked to ascertain whether the road section being used by the vehicle is a toll road section.
In the toll-collecting system of the invention at least one cell of the radio network can be assigned to a toll road section, and the system can be adapted to transmit cell IDs to the transmitter/receiver unit of the vehicle.
Conveniently, the radio network is a GSM network.
Other advantages can be achieved if the position-calculating system is satellite-aided, which position-calculating system is preferably a GPS system.
The road section identifying unit can be adapted, when using the primary position calculating system, to weight each cell assigned to a toll road section with a weight characteristic of the relevance of this cell for the recognition of the toll road section.
Furthermore, for the purpose of identifying a toll road section, the road section identifying unit can be adapted to form the sum of the weights of at least two cells assigned to said road section.
Additionally, the road section identifying unit can be adapted to classify the currently used road section as being a toll road section when a predefined threshold value of the sum of the weights is exceeded.
In an advantageous variant of the invention, the road section identifying unit can be adapted to count the number of the currently traversed cells assigned to a toll road section with reference to the cell IDs received by the transmitter/receiver unit and to check whether a predefined number of traversed cells has been exceeded.
In order to determine a toll road section, the road section identifying unit can be adapted to check whether at least two cell IDs successively received by the transmitter/receiver unit are assigned to the same toll road section.